The present invention relates to testing data packet signal transceivers, and in particular, to achieve faster test times by coordinating transmitted data packet signal powers to ensure settled output signal powers when measuring data packet signal characteristics.
Many of today's electronic devices use wireless technologies for both connectivity and communications purposes. Because wireless devices transmit and receive electromagnetic energy, and because two or more wireless devices have the potential of interfering with the operations of one another by virtue of their signal frequencies and power spectral densities, these devices and their wireless technologies must adhere to various wireless technology standard specifications.
When designing such wireless devices, engineers take extra care to ensure that such devices will meet or exceed each of their included wireless technology prescribed standard-based specifications. Furthermore, when these devices are later being manufactured in quantity, they are tested to ensure that manufacturing defects will not cause improper operation, including their adherence to the included wireless technology standard-based specifications.
For testing these devices following their manufacture and assembly, current wireless device test systems (also referred to as “testers”) employ a subsystem for analyzing signals received from each device. Such subsystems typically include at least a vector signal generator (VSG) for providing the source signals to be transmitted to the device under test, and a vector signal analyzer (VSA) for analyzing signals produced by the device under test. The production of test signals by the VSG and signal analysis performed by the VSA are generally programmable so as to allow each to be used for testing a variety of devices for adherence to a variety of wireless technology standards with differing frequency ranges, bandwidths and signal modulation characteristics.
As part of the manufacturing of wireless communication devices, one significant component of production cost is costs associated with manufacturing tests. Typically, there is a direct correlation between the cost of test and the time required to perform the test. Thus, innovations that can shorten test time without compromising test accuracy or increasing equipment costs (e.g., increasing costs due to increasing sophistication of necessary test equipment, or testers) are important and can provide significant costs savings, particularly in view of the large numbers of such devices being manufactured and tested.
As is well known, testing of wireless transceivers typically involves combinations of receiver (RX) and transmitter (TX) testing. Generally, there are no prescribed methods or requirements in terms of ordering or sequences of receiver and transmitter tests. For example, all receiver tests could be performed first followed by all transmitter tests, or vice versa. Indeed, it has been found that overall test time, e.g., the overall time required to do all standard-prescribed receiver and transmitter tests, can vary significantly, depending upon how the receiver and transmitter test are ordered, organized and performed.
For example, during transmitter testing where the device under test (DUT) is transmitting test data packets to a tester, during signal switching periods or whenever there is a change in signal frequency or power level, a time interval of output signal instability exists, during which the transmitter output power varies over some range of values as the output circuitry settles into its steady-state operation. Accordingly, following such a signal switching episode, a typical transmitter test procedure will disregard a number of the initially transmitted data packets so as to avoid false negatives caused by instabilities rather than by what may otherwise be perceived as a failure of the DUT. This time during which these initially transmitted test data packets are sent and ignored adds, sometimes significantly, to the overall test time. For example, in some instances, the time lost ignoring test data packets can be equal to or greater than the actual time necessary for the sequence of test data packets used to actually perform the intended test.
Accordingly, it would be desirable to have a technique for testing data transceivers in which time otherwise wasted for awaiting power settling of a transmitted data signal can be used for performing useful tasks associated with the test to be performed. Additionally, if such testing method could be applied to multiple DUTs for simultaneous testing, further time savings could be achieved.